In modern medical practice, it is sometimes desirable to pre-fill a number of syringes with an injectate (e.g, an injectable liquid), such that each syringe contains a predetermined volume and/or concentration of the injectate. Additionally, it is generally desirable to accomplish such filling of the syringes with little or no manual handling of the syringes, thereby freeing the hands of the physician for other tasks and/or minimizing the number of technicians or assistants who must be present in order to carry out the medical procedure.
In particular, various diagnostic imaging procedures (e.g., x-ray, nuclear magnetic resonance (NMR), ultrasound, etc.) require multiple injections of contrast solution to permit visualization of blood vessels or other anatomical structures by radiographic or other (e.g., magnetic, ultrasonic) imaging means. Such injections of contrast solution are typically carried out by pre-filling one or more syringes with radiographic contrast solution at the desired concentration(s) and volume(s). Thereafter, the pre-filled syringe(s) are utilized to deliver bolus injection(s) of contrast solution, during the radiological procedure.
It has been common practice to place a fresh vial or container of the desired contrast solution in the room wherein the imaging procedure is to be performed, along with one or more vials or bottles of diluent (e.g., 0.9% NaCl solution). Depending on the desired concentration of contrast solution to be injected and the number of such injections to be given, the physician or technician then proceeds to prefill one or more of the syringes by manually aspirating, into each syringe, i) a predetermined amount of the contrast solution from the first vial or bottle, and ii) a predetermined amount of the diluent from the second vial or bottle. In this manner, there are provided one or more prefilled syringe(s) which contain the desired volume(s) and concentration(s) of the contrast solution. However, such manual pre-filling of the syringes requires a substantial amount of handling and, in some procedures, may result in the need for an additional technician to be present in the procedure room to assist the physician in performing the procedure. Furthermore, such manual prefilling of syringes may be prone to human error, especially when various different dilutions or volume(s) of the contrast solution are being employed.
Additionally, once the fresh vial or bottle of contrast solution has been utilized at the patient's bed side, the infection control policies and practices of many healthcare institutions require that any left over contrast solution contained in that vial or bottle be discarded, rather than reusing the left-over solution in another procedure room for another patient. This can result in substantial waste of radiographic contrast solution, and may increase the expense of each imaging procedure performed.
The prior art has included various syringe filling devices and related apparatus which may be used to pre-fill medical syringes with injectate solutions. Examples of such syringe filling devices and/or related apparatus are found in U.S. Pat. Nos. 4,133,314 (Bloom et al.), 4,187,890 (Stach et al.), 4,253,501 (Ogle), 4,883,101 (Strong), 4,998,570 (Strong), 5,220,948 (Haber et al.), 5,329,974 (Paping), 5,341,854 (Zezulka et al.), 3,734,147 (Borutta et al.), 3,935,883 (Stach et al.), 5,450,847 (Kampfe et al.) and 5,592,940 (Kampfe et al.).
In particular, U.S. Pat. Nos. 5,450,847 (Kampfe et al.) and 5,592,940 (Kampfe et al.) describe an apparatus which is purportedly useable for mixing radiographic contrast solutions of varying concentration. The mixing apparatus described in U.S. Pat. Nos. 5,450,847 (Kampfe et al.) and 5,592,940 (Kampfe et al.) generally comprises; i.) a first tube or "pipe" connected to a container of concentrated radiographic contrast solution, ii.) a second tube or "pipe" connected to a container of diluent, iii.) a mixing chamber connected to the first and second pipes such that contrast solution and diluent from the respective containers may be received within the mixing chamber, and iv.) a delivery pipe which extends from the mixing chamber and terminates in an outlet to which a variety of receiving vessels (e.g., vials, bags or syringes) may be attached. Also, v.) metering apparatus are positioned on the first and second pipes to control the relative amounts of contrast solution and diluent which flow into the mixing chamber. Either gravity feed or pumps are used to feed the radiographic contrast solution and diluent through the respective first and second pipes and into the mixing chamber, wherein the resultant admixture of contrast solution/diluent is formed.
Notably, U.S. Pat. Nos. 5,450,847 (Kampfe et al.) and 5,592,940 (Kampfe et al.) do not describe or suggest the addition of a separate pump on the delivery pipe for controlling the passage of the admixture from the mixing chamber to the receiving vessel (e.g., bag, vial or syringe) connected to the outlet of the delivery pipe. Thus, the admixture which collects in the mixing chamber must be carried by gravity, or by the residual force of a pressure head created by any pumping devices located on the first and second pipes, into the final receiving vessel (e.g., bag, vial or syringe). Moreover, U.S. Pat. Nos. 5,540,847 (Kampfe et al.) and 5,592,940 (Kampfe et al.) do not describe or suggest the addition of any device for serially and/or automatically filling a number of individual syringes with the contrast solution/diluent admixture which flows out of the end of the delivery pipe.
Indeed, the apparatus described in U.S. Pat. Nos. 5,540,847 (Kampfe et al.) and 5,592,940 (Kampfe et al.) may be difficult or impossible to use for automated filling of multiple syringes without the need for manual connection and disconnection of each syringe to the outlet end of the delivery pipe, and/or manual pulling of the syringe plungers to facilitate the filling of such syringes.
In view of the above-mentioned shortcomings of the prior art, and others, there remains a need for the development of an improved apparatus for automated filling of numerous syringes, with equal or differing concentrations of radiographic contrast solution, so as to improve the efficiency and lessen the cost of radiological procedures wherein multiple injections of contrast solution are utilized.